Differences in cognitive function at 18 y of age explain the association between low education and early dementia risk.

Major initiatives attempt to prevent dementia by targeting modifiable risk factors. Low education is frequently pointed to, due to its relationship with dementia. Impact of education is difficult to assess, however, because of associations with multiple other factors, requiring large population-representative samples to tease the relationships apart. We studied 207,814 Norwegian men born between 1950 and 1959 who underwent compulsory cognitive testing during military conscription as young adults, to systematically test associations of education, cognition, and other important factors. Participants were grouped into five education levels and seven cognitive levels. A total of 1,521 were diagnosed with dementia between ages 60 and 69 y. While having compulsory education only was associated with increased risk (Hazard ratio [HR] = 1.37, CI: 1.17 to 1.60), this association was markedly attenuated when controlling for cognitive test scores (HR = 1.08, CI: 0.91 to 1.28). In contrast, low cognitive score was associated with double risk of later diagnosis, even when controlling for education (HR = 2.00, CI: 1.65 to 2.42). This relationship survived controlling for early-life socioeconomic status and replicated within pairs of brothers. This suggests that genetic and environmental factors shared within families, e.g., common genetics, parental education, socioeconomic status, or other shared experiences, cannot account for the association. Rather, independent, nonfamilial factors are more important. In contrast, within-family factors accounted for the relationship between low education and diagnosis risk. In conclusion, implementing measures to increase cognitive function in childhood and adolescence appears to be a more promising strategy for reducing dementia burden.

Adolescence and the next generation.

Adolescent growth and social development shape the early development of offspring from preconception through to the post-partum period through distinct processes in males and females. At a time of great change in the forces shaping adolescence, including the timing of parenthood, investments in today's adolescents, the largest cohort in human history, will yield great dividends for future generations.

Publisher Correction: Adolescence and the next generation.

In Fig. 4a of this Analysis, owing to an error during the production process, the year in the header of the right column was '2016' rather than '2010'. In addition, in the HTML version of the Analysis, Table 1 was formatted incorrectly. These errors have been corrected online.

Sex differences in cognitive decline among middle-aged and older adults: a cohort study in Europe.

OBJECTIVES: Previous studies on sex differences in cognitive decline provide inconsistent findings, with many European countries being underrepresented. We determined the association between sex and cognitive decline in a sample of Europeans and explored differences across birth cohorts and regions. METHODS: Participants 50+ years old enrolled in the Survey of Health, Ageing and Retirement in Europe had their cognition measured by tests of immediate recall, delayed recall and verbal fluency biennially up to 17 years of follow-up (median 6, interquartile range 3-9 years). We used linear mixed-effects models to assess the relationship between sex and the rate of cognitive decline, adjusting for sociodemographic and health-related characteristics. RESULTS: Of 66,670 participants (mean baseline age 63.5 ± standard deviation 9.4), 55% were female. Males and females had similar rates of decline in the whole sample in immediate recall (beta for interaction sex × time B = 0.002, 95% CI -0.001 to 0.006), delayed recall (B = 0.000, 95% CI -0.004 to 0.004), and verbal fluency (B = 0.008, 95% CI -0.005 to 0.020). Females born before World War II had a faster rate of decline in immediate recall and delayed recall compared to males, while females born during or after World War II had a slower rate of decline in immediate recall. Females in Central and Eastern Europe had a slower rate of cognitive decline in delayed recall compared to males. DISCUSSION: Our study does not provide strong evidence of sex differences in cognitive decline among older Europeans. However, we identified heterogeneity across birth cohorts and regions.

The Global Adolescent Fertility Decline is Counteracted by Increasing Teen Births in Sub-Saharan Africa.

There is a lack of understanding of the persistence of elevated teen fertility rates in certain regions and countries, in contrast to the significant decline observed in other regions globally. This report considers fertility trends among 15- to 19-year olds in the period 1950-2020 and explores potential driving factors behind the significant shifts that occurred over this period. The countries where teen fertility remains high are those with fast-growing populations, primarily located in sub-Saharan Africa. Countries with higher teen fertility are typically characterized by limited use of modern contraception, lower education levels, and early marriage. Sub-Saharan Africa has emerged as the world region with the most teen births, increasing its proportion of global teen births from 12 percent in 1950 to 47 percent in 2020, a time during which this region's share of the global adolescent (15-19) population grew from 7.5 percent to 19 percent. By 2035, 67 percent of all teen births globally are projected to occur in this region. Consequently, the future number of births to teenage mothers will to a large extent depend on the development in sub-Saharan Africa over the coming decades.

Retirement age and disability status as pathways to later-life cognitive impairment: Evidence from the Norwegian HUNT Study linked with Norwegian population registers.

BACKGROUND: Research shows that retirement age is associated with later-life cognition but has not sufficiently distinguished between retirement pathways. We examined how retirement age was associated with later-life dementia and mild cognitive impairment (MCI) for people who retired via the disability pathway (received a disability pension prior to old-age pension eligibility) and those who retired via the standard pathway. METHODS: The study sample comprised 7210 participants from the Norwegian Trøndelag Health Study (HUNT4 70+, 2017-2019) who had worked for at least one year in 1967-2019, worked until age 55+, and retired before HUNT4. Dementia and MCI were clinically assessed in HUNT4 70+ when participants were aged 69-85 years. Historical data on participants' retirement age and pathway were retrieved from population registers. We used multinomial regression to assess the dementia/MCI risk for women and men retiring via the disability pathway, or early (<67 years), on-time (age 67, old-age pension eligibility) or late (age 68+) via the standard pathway. RESULTS: In our study sample, 9.5% had dementia, 35.3% had MCI, and 28.1% retired via the disability pathway. The disability retirement group had an elevated risk of dementia compared to the on-time standard retirement group (relative risk ratio [RRR]: 1.64, 95% CI 1.14-2.37 for women, 1.70, 95% CI 1.17-2.48 for men). MCI risk was lower among men who retired late versus on-time (RRR, 0.76, 95% CI 0.61-0.95). CONCLUSION: Disability retirees should be monitored more closely, and preventive policies should be considered to minimize the dementia risk observed among this group of retirees.

Trends in ages at death of Norwegian centenarians: the 1870-1904 birth cohorts.

BACKGROUND: With rapidly rising life expectancy and ageing populations, interest has grown in the survival patterns and ages at death at the highest ages. In Scandinavia, the accumulation of very old population segments coupled with long-established, high-quality population registers permit meaningful analysis. METHODS: This study is based on individual level data from extinct Norwegian birth cohorts using data obtained from the Norwegian Civil Register System. We assess trends in the ages at death of centenarians in Norway for cohorts born between 1870 and 1904 for evidence of any secular increase using quantile regression. RESULTS: We observed that there is no upward trend in centenarian lifespans, in line with recent observations in Sweden, but contrary to the upward trend at the very highest percentiles as observed in Denmark. CONCLUSIONS: The available evidence suggests that the stagnation in centenarian lifespans may be partly due to the failure to find ways of dealing with neurodegenerative diseases.

Job loss and psychological distress during the COVID-19 pandemic: a national prospective cohort study.

BACKGROUND: The COVID-19 pandemic caused substantial increases in unemployment; however, the association between these job losses and psychological distress is not well documented. Our study reports on this association from a cohort study, with a particular focus on educational differences in both the likelihood of job loss and its potential implications for mental health. METHODS: Utilizing data from a large prospective cohort study of parents in Norway (n = 58,982), we examined changes in psychological distress within four groups of respondents: those who during the first wave of COVID-19 had (i) no change in their employment situation, (ii) worked from home, (iii) been furloughed, or (iv) lost their job. RESULTS: Psychological distress increased in all groups. In z-scores relative to pre-pandemic levels, the increases were (i) 0.47 [95%-CI: 0.45-0.49] among respondents with no change in their employment situation, (ii) 0.51 [95%-CI: 0.49-0.53] among respondents who worked from home, (iii) 0.95 [95%-CI:0.91-0.99] among those furloughed, and (iv) 1.38 [95%-CI: 1.16-1.59] among those who permanently lost their job, corresponding to increases of 89%, 95%, 170%, and 185%, respectively. While respondents without university education had a 2 to 3 times higher risk of job loss, the negative impact of job loss on psychological distress was similar across educational levels. CONCLUSIONS: Participants exposed to job loss during the pandemic experienced a stronger increase in symptoms of depression or anxiety compared to those who remained employed. Although higher education lowered the risk of losing work, it did not substantially diminish the impact on mental health from losing work.

Trends in the use of home care services among Norwegians 70+ and projections towards 2050: The HUNT study 1995-2017.

BACKGROUND: Life expectancy (LE) is increasing worldwide, while there is lack of information on how this affects older individuals' use of formal home care services. AIM: We aimed to decompose LE into years with and without home care services and estimate projected number of users towards 2050 in Norway for people 70 years or older. METHODS: This study is based on a sample of 25,536 participants aged 70 years and older in the Trøndelag Health Study (HUNT) survey 2 (1995-1997), 3 (2006-2008), or 4 (2017-2019) linked with national data on mortality. Prevalence of home care services was standardised to the Norwegian population by age and sex. The Sullivan method was used to estimate expected years with and without home help services and nursing services for the years 1995, 2006 and 2016. Data from HUNT4 and Statistics Norway were used to estimate projected use of these services between 2020 and 2050. RESULTS: During 1995-2017, the use of home help services decreased from 22.6% to 6.2% (p < 0.001), and from 6.4% to 5.5% (p = 0.004) for home nursing services. Adjusted for age and sex, the use of home help services decreased significantly over time (p < 0.001), while home nursing services were stable (p = 0.69). LE at age 70 increased from 11.9 to 15.3 years in men (p < 0.05) during 1995-2017, and from 14.7 to 17.1 in women (p < 0.05). In the same period, the expected years receiving home help decreased from 2.6 to 1.1 in men (p < 0.05), and from 4.4 to 2.1 in women (p < 0.05). The expected years receiving home nursing increased from 0.6 to 0.9 in men (p < 0.05), and from 1.3 to 1.7 in women (p < 0.05). Projected numbers of people 70+ in Norway in need of either of these services were estimated to rise from 64,000 in 2020 to 160,000 in 2050. CONCLUSION: While overall life expectancy increased, the expected years receiving home help have decreased and home nursing slightly increased among the Norwegian population aged 70 years and older during 1995-2017. However, the substantial increase in the projected number of older adults using home care services in the future is an alert for the current health care planners.

Emerging costs in a "hidden" workforce: The longitudinal psychosocial effects of caregiving during the COVID-19 pandemic among Norwegian adults.

During COVID-19 many informal caregivers experienced increased caregiving load while access to formal and informal support systems and coping resources decreased. Little is known about the psychosocial costs of these challenges for an essential yet vulnerable and "hidden" frontline workforce. This study explores and compares changes in psychosocial well-being (psychological well-being, psychological ill-being, and loneliness) before and across up to three stages of the COVID-19 pandemic among caregivers and non-caregivers. We also examine predictors of psychosocial well-being among caregivers during the peak of the pandemic. We use longitudinal data collected online in the Norwegian Counties Public Health Survey (age: 18-92) in four counties and up to four data points (n = 14,881). Caregivers are those who provide care unpaid, continuous (≥ monthly across all time points) help to someone with health problems. Findings show that levels of psychosocial well-being first remained stable but later, during the peak stages of the pandemic, dropped markedly. Caregivers (13-15% of the samples) report lower psychosocial well-being than non-caregivers both before and during the pandemic. Caregivers seem especially vulnerable in terms of ill-being, and during the peak of the pandemic caregivers report higher net levels of worry (OR = 1.22, p < 0.01) and anxiety (OR = 1.23, p < 0.01) than non-caregivers. As expected, impacts are graver for caregivers who provide more intensive care and those reporting health problems or poor access to social support. Our study findings are valuable information for interventions to support caregivers during this and future pandemics.

Technology-induced job loss risk, disability and all-cause mortality in Norway.

BACKGROUND: Ongoing shifts in economic structure from automation and globalisation can affect employment and mortality, yet these relations are not well described. OBJECTIVE: We assess whether long-term employment and health outcomes relate systematically to structural change in the labour market, using the occupational Routine Task Intensity (RTI) score as indicator of exposure is to risks of outsourcing and technology-induced job loss. METHODS: Using a cohort design and administrative data with national population coverage, we categorise all Norwegian employees in 2003 by the RTI score of their occupation and examine how this score correlates with employment and health outcomes measured in 2018 and 2019. The study sample counts 416 003 men and 376 413 women aged 33-52 in 2003. RESULTS: The occupational RTI score at baseline is robustly associated with long-term employment, disability and mortality outcomes. Raw correlations are reduced after adjustment for potential confounders, but associations remain substantial in models controlling for individual covariates and in sibling comparisons. Working in an occupation with RTI score 1 SD above the mean in 2003 is associated with a raised probability of being deceased in 2019 of 0.24 percentage points (95% CI: 0.18 to 0.30) for men and 0.13 percentage points (95% CI: 0.02 to 0.24) for women, corresponding to raised mortality rates of 6.7% and 5.5%. CONCLUSIONS: Individuals in occupations characterised by high routine intensity are less likely to remain employed in the long term, and have higher rates of disability and mortality.

Does Childbearing Affect Cognitive Health in Later Life? Evidence From an Instrumental Variable Approach.

Cognitive decline is a widespread concern as populations grow older. However, population aging is partly driven by a decrease in fertility, and family size may influence cognitive functioning in later life. Prior studies have shown that fertility history is associated with late-life cognition, but whether the relationship is causal remains unclear. We use an instrumental variable approach and data from the Survey of Health, Ageing, and Retirement in Europe to examine whether having three or more versus two children affects late-life cognition. Parents often prefer to have at least one son and one daughter. We thus exploit the sex composition of the first two children as a source of exogenous variation in the probability of having three or more children. Results indicate that having three or more versus two children has a negative effect on late-life cognition. This effect is strongest in Northern Europe, perhaps because higher fertility decreases financial resources yet does not improve social resources in this region. Future studies should address the potential effects of childlessness or having one child on late-life cognition and explore the mediating mechanisms.

Trends in Disability-Free Life Expectancy (DFLE) from 1995 to 2017 in the older Norwegian population by sex and education: The HUNT Study.

AIM: Understanding whether increasing Life Expectancy (LE) translates to improved health and function among older adults is essential, but results are inconclusive. We aimed to estimate trends in Disability-Free Life Expectancy (DFLE) in the older Norwegian population by sex and education from 1995 to 2017. METHOD: National life table data were combined with cross-sectional data on functional ability for 70+ year-olds from the population-based Trøndelag Health Surveys 2-4 (1995-1997, 2006-2008 and 2017-2019) (n=24,733). Self-reported functional ability was assessed on a graded scale by a combination of Instrumental Activities of Daily Living (IADL) such as paying bills, going out or shopping (mild disability) and Personal Activities of Daily Living (PADL) such as washing, dressing or eating (severe disability). LE, DFLE, Mild-Disability LE and Severe-Disability LE at age 70 were estimated by the Sullivan method. RESULTS: From 1995 to 2017 DFLE at age 70 increased from 8.4 to 13.0 years in women, and from 8.0 to 12.1 years in men. DFLE increased in the basic and high educational groups, but more so in the high educational group among men. Educational inequalities in years spent with disability however, remained low. CONCLUSIONS: From the mid-1990s and over the past three decades both LE and DFLE at 70 years increased in the older Norwegian population, for both men and women, and across basic and high educational levels. Educational inequalities in DFLE increased, especially in men, but years spent with disability were similar across the three decades.

Hearing loss, sick leave, and disability pension: findings from the HUNT follow-up study.

BACKGROUND: Evidence on the association between hearing loss and sick leave or disability pension is to a great extent based on few cross-sectional studies and remains unclear. We aim to assess the associations in a long-term follow-up population study. METHODS: We used baseline data from a large population-based hearing study in Norway, the HUNT Hearing study (1996-1998). The sample included 21 754 adults (48.5% men, mean age at baseline 36.6 years). We used register data on sick leave and disability pension (1996-2011). Cox regression was used to assess the association between hearing loss at baseline (Pure tone average/PTA 0.5-4 kHz > 20 dB) and time to first physician-certified sick leave episode, as well as time to first disability pension payment. RESULTS: Hearing loss at baseline (yes/no) was weakly associated with time to first physician-certified sick leave episode: Hazard ratio (HR) 1.2 (95% confidence interval (CI) 1.1-1.3). Restricting the exposed group to people with both hearing loss and tinnitus, the HR was slightly increased: 1.3 (95% CI 1.1-1.6). Hearing loss in 1996-1998 was also associated with time to first received disability pension: HR 1.5 (95% CI 1.3-1.8). Stronger associations were found for disabling hearing loss (PTA > 35). Restricting the exposure to hearing loss and tinnitus, the HR was increased: 2.0 (95% CI 1.4-2.8). CONCLUSIONS: This large population-based cohort study indicates that hearing loss is associated with increased risk of receiving disability pension, especially among younger adults and low educated workers. Hearing loss was weakly associated with sick leave.

Preferred life expectancy and the association with hypothetical adverse life scenarios among Norwegians aged 60.

BACKGROUND: how long older individuals prefer to live given hypothetical adverse changes in health and living conditions has been insufficiently studied. OBJECTIVES: the objective of this study is to investigate the relationship between six adverse health and living conditions and preferred life expectancy (PLE) after the age of 60 years. DESIGN: cross-sectional face-to-face interviews. SETTING: population-based sample. PARTICIPANTS: 825 community dwellers aged 60 years and older in Norway. METHODS: logistic regression models were used to analyse PLE, measured with a single question: 'If you could choose freely, until what age would you wish to live?' The impact on PLE of several hypothetical scenarios, such as being diagnosed with dementia, spousal death, becoming a burden, poverty, loneliness and chronic pain was analysed by age, sex, education, marital status, cognitive function, self-reported loneliness and chronic pain. RESULTS: average PLE was 91.4 years (95% CI 90.9, 92.0), and there was no difference between men and women, but those at older ages had higher PLE than those at younger ages. The scenarios that had the strongest negative effects on PLE were dementia, followed by chronic pain, being a burden to society, loneliness, poverty and losing one's spouse. PLE among singles was not affected by the prospect of feeling lonely. The higher educated had lower PLE for dementia and chronic pain. CONCLUSION: among Norwegians 60+, the desire to live into advanced ages is significantly reduced by hypothetical adverse life scenarios, with the strongest effect caused by dementia and chronic pain.

Cohort profile: Norwegian survey of health and ageing (NORSE).

PURPOSE: The Norwegian Survey of Health and Ageing (NORSE) was set up to provide internationally comparable data on ageing in Norway, which includes measured intrinsic capacity and cognitive function. PARTICIPANTS: NORSE is a population-based health examination study of seniors aged 60+ from the 1921-1958 birth cohorts in the former Norwegian county of Oppland, interviewed and examined during 2017-19 (N = 957, 16% response rate). NORSE is to some extent based on the SHARE-questionnaire ( share-project.org ), which includes work-related information, self-assessed and retrospective health, and expectations on longevity, quality of life, volunteering activities, consumption, and financial arrangements. In addition, several objective measures of intrinsic and cognitive capacity are included in NORSE. FINDINGS TO DATE: A shorter preferred life expectancy (PLE) was found to be associated with the prospects of a life with dementia and chronic pain. Motivation for retirement was found to be related to work-life experience and health. Social media was mostly used in the younger age groups and there was a tendency towards more use in the higher educational groups. NORSE incorporates questions on religion, and older women tend to have a higher degree of religiosity (proxied as self-assessed religiosity) than men in their 80s, but more similar (and lower levels) among those in their 60s. FUTURE PLANS: NORSE participants have allowed their data to be linked to National registry data and midlife health examination studies and thereby provide a longitudinal design as well as information on disability status, socioeconomic status, household and marital status, support to/from children and parents, and pension status.

Progress in adolescent health and wellbeing: tracking 12 headline indicators for 195 countries and territories, 1990-2016.

BACKGROUND: Rapid demographic, epidemiological, and nutritional transitons have brought a pressing need to track progress in adolescent health. Here, we present country-level estimates of 12 headline indicators from the Lancet Commission on adolescent health and wellbeing, from 1990 to 2016. METHODS: Indicators included those of health outcomes (disability-adjusted life-years [DALYs] due to communicable, maternal, and nutritional diseases; injuries; and non-communicable diseases); health risks (tobacco smoking, binge drinking, overweight, and anaemia); and social determinants of health (adolescent fertility; completion of secondary education; not in education, employment, or training [NEET]; child marriage; and demand for contraception satisfied with modern methods). We drew data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2016, International Labour Organisation, household surveys, and the Barro-Lee education dataset. FINDINGS: From 1990 to 2016, remarkable shifts in adolescent health occurred. A decrease in disease burden in many countries has been offset by population growth in countries with the poorest adolescent health profiles. Compared with 1990, an additional 250 million adolescents were living in multi-burden countries in 2016, where they face a heavy and complex burden of disease. The rapidity of nutritional transition is evident from the 324·1 million (18%) of 1·8 billion adolescents globally who were overweight or obese in 2016, an increase of 176·9 million compared with 1990, and the 430·7 million (24%) who had anaemia in 2016, an increase of 74·2 million compared with 1990. Child marriage remains common, with an estimated 66 million women aged 20-24 years married before age 18 years. Although gender-parity in secondary school completion exists globally, prevalence of NEET remains high for young women in multi-burden countries, suggesting few opportunities to enter the workforce in these settings. INTERPRETATION: Although disease burden has fallen in many settings, demographic shifts have heightened global inequalities. Global disease burden has changed little since 1990 and the prevalence of many adolescent health risks have increased. Health, education, and legal systems have not kept pace with shifting adolescent needs and demographic changes. Gender inequity remains a powerful driver of poor adolescent health in many countries. FUNDING: Australian National Health and Medical Research Council, and the Bill & Melinda Gates Foundation.

Fathers of children conceived using ART have higher cognitive ability scores than fathers of naturally conceived children.

STUDY QUESTION: Does paternal cognitive ability differ for children conceived with and without assisted reproductive technology (ART)? SUMMARY ANSWER: Young fathers of ART conceived children tend to score cognitively below their same-age natural conception (NC) counterparts and older (above 35) fathers of ART conceived children tend to score above. WHAT IS KNOWN ALREADY: Cognitive ability is a genetically and socially transmitted trait, and If ART and NC children have parents with different levels of this trait, then this would in itself predict systematic differences in child cognitive outcomes. Research comparing cognitive outcomes of children with different modes of conception finds conflicting results, and studies may be influenced by selection and confounding. STUDY DESIGN, SIZE, DURATION: This is a population-based study based on Norwegian data, combining information from the Medical Birth Registry (births through 2012), military conscription tests (birth cohorts 1955-1977) and the population registry. These data allow us to compare the cognitive ability scores of men registered as the father of an ART-conceived child to the cognitive abilities of other fathers and to average scores in the paternal birth cohorts. PARTICIPANTS/MATERIALS, SETTINGS, METHODS: The population level study included 18 566 births after ART (5810 after ICSI, 12 756 after IVF), and 1 048 138 NC births. It included all Norwegian men who received a cognitive ability score after attending military conscription between 1973 and 1995. This constituted 614 827 men (89.4% of the male birth cohorts involved). An additional 77 650 unscored males were included in sensitivity analyses. MAIN RESULTS AND THE ROLE OF CHANCE: Paternal cognitive level was assessed using intelligence quotients (IQ) converted from stanine scores on a three-part cognitive ability test with items measuring numeracy, vocabulary and abstract thought (Raven-like matrices). ART fathers averaged 1.95 IQ points above the average of their own birth cohort (P-value < 0.0005) and 1.83 IQ points above NC fathers in their own birth cohort (P < 0.0005). Comparisons of the IQ of ART fathers to those of NC fathers of similar age and whose children were born in the same year, however, found average scores to be more similar (point estimate 0.24, P = 0.023). These low average differences were found to differ substantially by age of fatherhood, with young ART fathers scoring below their NC counterparts and older ART fathers scoring above their NC counterparts. LIMITATIONS, REASONS FOR CAUTION: We do not have information on maternal cognition. We also lack information on unsuccessful infertility treatments that did not result in a live birth. WIDER IMPLICATIONS OF THE FINDINGS: Paternal cognitive ability of ART children differs from that of NC children, and this difference varies systematically with paternal age at child birth. Selection effects into ART may help explain differences between ART and NC children and need to be adequately controlled for when assessing causal effects of ART treatment on child outcomes. STUDY FUNDING/COMPETING INTEREST(S): This research has also been supported by the Research Council of Norway through its Centres of Excellence funding scheme, project number 262700 (Centre for Fertility and Health). It has also been supported by the Research Council of Norway's Project 236992 (Egalitarianism under pressure? New perspectives on inequality and social cohesion). There are no competing interests. TRIAL REGISTRATION NUMBER: N/A.

Childlessness and union histories: evidence from Finnish population register data.

From an evolutionary perspective, childlessness may be considered a failure, as it implies that there will be no direct transmission of one's genetic material to later generations. It is also a pressing social issue, because in many contemporary advanced societies, levels of childlessness have increased, and particularly so among men. The absence of a partner is naturally a fundamental determinant of childlessness. Empirical evidence on how childlessness relates to individuals' partnership histories is nevertheless limited. This issue was analysed with Finnish population register data, which allow the complete cohabitation and marriage histories of individuals from age 18 years to be observed. For women and men born between 1969 and 1971, logistic regression models were estimated for childlessness at age 40 by partnership histories in terms of various stages in the process of union formation and dissolution, and accounting for several socioeconomic variables. A strong link between union histories and childlessness was found, with short partnership spells raising the risk of not becoming a parent. Later age when leaving the parental home raised female childlessness, while a short first-union duration related more strongly to male childlessness. These findings may be considered as providing insights into how specific life-history strategies affect reproductive outcomes, and highlight the need to develop new approaches to understand this feature of social inequality.

How to Measure Population Aging? The Answer Is Less than Obvious: A Review.

Usually, population aging is measured to inform fiscal and social planning because it is considered to indicate the burden that an elderly population presents to the economic, social security, and health systems of a society. Measures of population aging are expected to indicate shifts in the distribution of individuals' attributes (e.g., chronological age, health) within a population that are relevant to assessing the burden. We claim that chronological age - even though it is the attribute most broadly used - may frequently not be the best measure to satisfy this purpose. A distribution of chronological age per se does not present a burden. Rather, burdens arise from the characteristics that supposedly or actually accompany chronological ages. We posit that in addition to chronological age, meaningful measures of population aging should reflect, for instance, the distribution of economic productivity, health, functional capacities, or biological age, as these attributes may more directly assess the burden on the socioeconomic and health systems. Here, we illustrate some limitations of measures of population aging based on each kind of measure, including chronological age, and review alternative measures that may better inform fiscal, social, and health planning.